feat(pdfengines): add bookmarks write route and update the merge route with this feature

pkg/gotenberg/mocks.go

@@ -46,14 +46,15 @@ func (mod *DebuggableMock) Debug() map[string]any {
 //
 //nolint:dupl
 type PdfEngineMock struct {
-	MergeMock         func(ctx context.Context, logger *zap.Logger, inputPaths []string, outputPath string) error
+	MergeMock          func(ctx context.Context, logger *zap.Logger, inputPaths []string, outputPath string) error
-	SplitMock         func(ctx context.Context, logger *zap.Logger, mode SplitMode, inputPath, outputDirPath string) ([]string, error)
+	SplitMock          func(ctx context.Context, logger *zap.Logger, mode SplitMode, inputPath, outputDirPath string) ([]string, error)
-	FlattenMock       func(ctx context.Context, logger *zap.Logger, inputPath string) error
+	FlattenMock        func(ctx context.Context, logger *zap.Logger, inputPath string) error
-	ConvertMock       func(ctx context.Context, logger *zap.Logger, formats PdfFormats, inputPath, outputPath string) error
+	ConvertMock        func(ctx context.Context, logger *zap.Logger, formats PdfFormats, inputPath, outputPath string) error
-	ReadMetadataMock  func(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]any, error)
+	ReadMetadataMock   func(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]any, error)
-	WriteMetadataMock func(ctx context.Context, logger *zap.Logger, metadata map[string]any, inputPath string) error
+	WriteMetadataMock  func(ctx context.Context, logger *zap.Logger, metadata map[string]any, inputPath string) error
-	EncryptMock       func(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error
+	EncryptMock        func(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error
-	EmbedFilesMock    func(ctx context.Context, logger *zap.Logger, filePaths []string, inputPath string) error
+	EmbedFilesMock     func(ctx context.Context, logger *zap.Logger, filePaths []string, inputPath string) error
+	WriteBookmarksMock func(ctx context.Context, logger *zap.Logger, inputPath string, bookmarks []Bookmark) error
 }
 
 func (engine *PdfEngineMock) Merge(ctx context.Context, logger *zap.Logger, inputPaths []string, outputPath string) error {
@@ -88,6 +89,10 @@ func (engine *PdfEngineMock) EmbedFiles(ctx context.Context, logger *zap.Logger,
 	return engine.EmbedFilesMock(ctx, logger, filePaths, inputPath)
 }
 
+func (engine *PdfEngineMock) WriteBookmarks(ctx context.Context, logger *zap.Logger, inputPath string, bookmarks []Bookmark) error {
+	return engine.WriteBookmarksMock(ctx, logger, inputPath, bookmarks)
+}
+
 // PdfEngineProviderMock is a mock for the [PdfEngineProvider] interface.
 type PdfEngineProviderMock struct {
 	PdfEngineMock func() (PdfEngine, error)

pkg/gotenberg/pdfengine.go

@@ -109,6 +109,14 @@ type PdfFormats struct {
 	PdfUa bool
 }
 
+// Bookmark represents a node in the PDF document's outline
+// (table of contents).
+type Bookmark struct {
+	Title    string     `json:"title"`
+	Page     int        `json:"page"`
+	Children []Bookmark `json:"children,omitempty"`
+}
+
 // PdfEngine provides an interface for operations on PDFs. Implementations
 // can use various tools like PDFtk, or implement functionality directly in
 // Go.
@@ -138,6 +146,10 @@ type PdfEngine interface {
 	// WriteMetadata writes the metadata into a given PDF file.
 	WriteMetadata(ctx context.Context, logger *zap.Logger, metadata map[string]any, inputPath string) error
 
+	// WriteBookmarks adds a document outline (bookmarks) to a PDF file.
+	// The bookmarks parameter represents the hierarchical tree of the outline.
+	WriteBookmarks(ctx context.Context, logger *zap.Logger, inputPath string, bookmarks []Bookmark) error
+
 	// Encrypt adds password protection to a PDF file.
 	// The userPassword is required to open the document.
 	// The ownerPassword provides full access to the document.
@@ -146,6 +158,7 @@ type PdfEngine interface {
 
 	// EmbedFiles embeds files into a PDF. All files are embedded as file attachments
 	// without modifying the main PDF content.
+	// TODO: attachments instead? Rename the route?
 	EmbedFiles(ctx context.Context, logger *zap.Logger, filePaths []string, inputPath string) error
 }
 

pkg/modules/exiftool/exiftool.go

@@ -203,6 +203,11 @@ func (engine *ExifTool) WriteMetadata(ctx context.Context, logger *zap.Logger, m
 	return nil
 }
 
+// WriteBookmarks is not available in this implementation.
+func (engine *ExifTool) WriteBookmarks(ctx context.Context, logger *zap.Logger, inputPath string, bookmarks []gotenberg.Bookmark) error {
+	return fmt.Errorf("write PDF bookmarks with ExifTool: %w", gotenberg.ErrPdfEngineMethodNotSupported)
+}
+
 // Encrypt is not available in this implementation.
 func (engine *ExifTool) Encrypt(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error {
 	return fmt.Errorf("encrypt PDF using ExifTool: %w", gotenberg.ErrPdfEncryptionNotSupported)

pkg/modules/libreoffice/pdfengine/pdfengine.go

@@ -91,6 +91,11 @@ func (engine *LibreOfficePdfEngine) WriteMetadata(ctx context.Context, logger *z
 	return fmt.Errorf("write PDF metadata with LibreOffice: %w", gotenberg.ErrPdfEngineMethodNotSupported)
 }
 
+// WriteBookmarks is not available in this implementation.
+func (engine *LibreOfficePdfEngine) WriteBookmarks(ctx context.Context, logger *zap.Logger, inputPath string, bookmarks []gotenberg.Bookmark) error {
+	return fmt.Errorf("write PDF bookmarks with LibreOffice: %w", gotenberg.ErrPdfEngineMethodNotSupported)
+}
+
 // Encrypt is not available in this implementation.
 func (engine *LibreOfficePdfEngine) Encrypt(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error {
 	return fmt.Errorf("encrypt PDF using LibreOffice: %w", gotenberg.ErrPdfEngineMethodNotSupported)

pkg/modules/pdfcpu/pdfcpu.go

@@ -171,6 +171,11 @@ func (engine *PdfCpu) WriteMetadata(ctx context.Context, logger *zap.Logger, met
 	return fmt.Errorf("write PDF metadata with pdfcpu: %w", gotenberg.ErrPdfEngineMethodNotSupported)
 }
 
+// WriteBookmarks is not available in this implementation.
+func (engine *PdfCpu) WriteBookmarks(ctx context.Context, logger *zap.Logger, inputPath string, bookmarks []gotenberg.Bookmark) error {
+	return fmt.Errorf("write PDF bookmarks with pdfcpu: %w", gotenberg.ErrPdfEngineMethodNotSupported)
+}
+
 // EmbedFiles embeds files into a PDF. All files are embedded as file attachments
 // without modifying the main PDF content.
 func (engine *PdfCpu) EmbedFiles(ctx context.Context, logger *zap.Logger, filePaths []string, inputPath string) error {

pkg/modules/pdfengines/multi.go

@@ -20,6 +20,7 @@ type multiPdfEngines struct {
 	writeMetadataEngines []gotenberg.PdfEngine
 	passwordEngines      []gotenberg.PdfEngine
 	embedEngines         []gotenberg.PdfEngine
+	bookmarksEngines     []gotenberg.PdfEngine
 }
 
 func newMultiPdfEngines(
@@ -30,7 +31,8 @@ func newMultiPdfEngines(
 	readMetadataEngines,
 	writeMetadataEngines,
 	passwordEngines,
-	embedEngines []gotenberg.PdfEngine,
+	embedEngines,
+	bookmarksEngines []gotenberg.PdfEngine,
 ) *multiPdfEngines {
 	return &multiPdfEngines{
 		mergeEngines:         mergeEngines,
@@ -41,6 +43,7 @@ func newMultiPdfEngines(
 		writeMetadataEngines: writeMetadataEngines,
 		passwordEngines:      passwordEngines,
 		embedEngines:         embedEngines,
+		bookmarksEngines:     bookmarksEngines,
 	}
 }
 
@@ -266,6 +269,31 @@ func (multi *multiPdfEngines) EmbedFiles(ctx context.Context, logger *zap.Logger
 	return fmt.Errorf("embed files into PDF using multi PDF engines: %w", err)
 }
 
+// WriteBookmarks adds a document outline (bookmarks) to a PDF file using the
+// first available engine that supports metadata writing.
+func (multi *multiPdfEngines) WriteBookmarks(ctx context.Context, logger *zap.Logger, inputPath string, bookmarks []gotenberg.Bookmark) error {
+	var err error
+	errChan := make(chan error, 1)
+
+	for _, engine := range multi.bookmarksEngines {
+		go func(engine gotenberg.PdfEngine) {
+			errChan <- engine.WriteBookmarks(ctx, logger, inputPath, bookmarks)
+		}(engine)
+
+		select {
+		case writeBookmarksErr := <-errChan:
+			errored := multierr.AppendInto(&err, writeBookmarksErr)
+			if !errored {
+				return nil
+			}
+		case <-ctx.Done():
+			return ctx.Err()
+		}
+	}
+
+	return fmt.Errorf("write PDF bookmarks with multi PDF engines: %w", err)
+}
+
 // Interface guards.
 var (
 	_ gotenberg.PdfEngine = (*multiPdfEngines)(nil)

pkg/modules/pdfengines/pdfengines.go

@@ -36,6 +36,7 @@ type PdfEngines struct {
 	writeMetadataNames []string
 	encryptNames       []string
 	embedNames         []string
+	bookmarksNames     []string
 	engines            []gotenberg.PdfEngine
 	disableRoutes      bool
 }
@@ -54,6 +55,7 @@ func (mod *PdfEngines) Descriptor() gotenberg.ModuleDescriptor {
 			fs.StringSlice("pdfengines-write-metadata-engines", []string{"exiftool"}, "Set the PDF engines and their order for the write metadata feature - empty means all")
 			fs.StringSlice("pdfengines-encrypt-engines", []string{"qpdf", "pdftk", "pdfcpu"}, "Set the PDF engines and their order for the password protection feature - empty means all")
 			fs.StringSlice("pdfengines-embed-engines", []string{"pdfcpu"}, "Set the PDF engines and their order for the file embedding feature - empty means all")
+			fs.StringSlice("pdfengines-bookmarks-engines", []string{"pdfcpu", "pdftk"}, "Set the PDF engines and their order for the bookmarks feature - empty means all")
 			fs.Bool("pdfengines-disable-routes", false, "Disable the routes")
 
 			// Deprecated flags.
@@ -81,6 +83,7 @@ func (mod *PdfEngines) Provision(ctx *gotenberg.Context) error {
 	writeMetadataNames := flags.MustStringSlice("pdfengines-write-metadata-engines")
 	encryptNames := flags.MustStringSlice("pdfengines-encrypt-engines")
 	embedNames := flags.MustStringSlice("pdfengines-embed-engines")
+	bookmarksNames := flags.MustStringSlice("pdfengines-bookmarks-engines")
 	mod.disableRoutes = flags.MustBool("pdfengines-disable-routes")
 
 	engines, err := ctx.Modules(new(gotenberg.PdfEngine))
@@ -147,6 +150,11 @@ func (mod *PdfEngines) Provision(ctx *gotenberg.Context) error {
 		mod.embedNames = embedNames
 	}
 
+	mod.bookmarksNames = defaultNames
+	if len(bookmarksNames) > 0 {
+		mod.bookmarksNames = bookmarksNames
+	}
+
 	return nil
 }
 
@@ -196,6 +204,7 @@ func (mod *PdfEngines) Validate() error {
 	findNonExistingEngines(mod.writeMetadataNames)
 	findNonExistingEngines(mod.encryptNames)
 	findNonExistingEngines(mod.embedNames)
+	findNonExistingEngines(mod.bookmarksNames)
 
 	if len(nonExistingEngines) == 0 {
 		return nil
@@ -215,6 +224,8 @@ func (mod *PdfEngines) SystemMessages() []string {
 		fmt.Sprintf("read metadata engines - %s", strings.Join(mod.readMetadataNames[:], " ")),
 		fmt.Sprintf("write metadata engines - %s", strings.Join(mod.writeMetadataNames[:], " ")),
 		fmt.Sprintf("encrypt engines - %s", strings.Join(mod.encryptNames[:], " ")),
+		fmt.Sprintf("embed engines - %s", strings.Join(mod.embedNames[:], " ")),
+		fmt.Sprintf("bookmarks engines - %s", strings.Join(mod.bookmarksNames[:], " ")),
 	}
 }
 
@@ -243,6 +254,7 @@ func (mod *PdfEngines) PdfEngine() (gotenberg.PdfEngine, error) {
 		engines(mod.writeMetadataNames),
 		engines(mod.encryptNames),
 		engines(mod.embedNames),
+		engines(mod.bookmarksNames),
 	), nil
 }
 
@@ -266,6 +278,7 @@ func (mod *PdfEngines) Routes() ([]api.Route, error) {
 		convertRoute(engine),
 		readMetadataRoute(engine),
 		writeMetadataRoute(engine),
+		writeBookmarksRoute(engine),
 		encryptRoute(engine),
 		embedRoute(engine),
 	}, nil

pkg/modules/pdfengines/routes.go

@@ -84,7 +84,7 @@ func FormDataPdfSplitMode(form *api.FormData, mandatory bool) gotenberg.SplitMod
 }
 
 // FormDataPdfFormats creates [gotenberg.PdfFormats] from the form data.
-// Fallback to default value if the considered key is not present.
+// Fallback to the default value if the considered key is not present.
 func FormDataPdfFormats(form *api.FormData) gotenberg.PdfFormats {
 	var (
 		pdfa  string
@@ -128,6 +128,44 @@ func FormDataPdfMetadata(form *api.FormData, mandatory bool) map[string]any {
 	return metadata
 }
 
+// FormDataPdfBookmarks creates bookmarks from the form data.
+func FormDataPdfBookmarks(form *api.FormData, mandatory bool) any {
+	var bookmarks any
+
+	bookmarksFunc := func(value string) error {
+		if len(value) > 0 {
+			var list []gotenberg.Bookmark
+			err := json.Unmarshal([]byte(value), &list)
+			if err == nil {
+				bookmarks = list
+				return nil
+			}
+
+			var m map[string][]gotenberg.Bookmark
+			err = json.Unmarshal([]byte(value), &m)
+			if err == nil {
+				bookmarks = m
+				return nil
+			}
+
+			return fmt.Errorf("unmarshal bookmarks: %w", err)
+		}
+		return nil
+	}
+
+	if mandatory {
+		form.MandatoryCustom("bookmarks", func(value string) error {
+			return bookmarksFunc(value)
+		})
+	} else {
+		form.Custom("bookmarks", func(value string) error {
+			return bookmarksFunc(value)
+		})
+	}
+
+	return bookmarks
+}
+
 // MergeStub merges given PDFs. If only one input PDF, it does nothing and
 // returns the corresponding input path.
 func MergeStub(ctx *api.Context, engine gotenberg.PdfEngine, inputPaths []string) (string, error) {
@@ -254,6 +292,42 @@ func WriteMetadataStub(ctx *api.Context, engine gotenberg.PdfEngine, metadata ma
 	return nil
 }
 
+// WriteBookmarksStub writes the bookmarks into PDF files. If no bookmarks, it
+// does nothing.
+func WriteBookmarksStub(ctx *api.Context, engine gotenberg.PdfEngine, bookmarks any, inputPaths []string) error {
+	if bookmarks == nil {
+		return nil
+	}
+
+	switch b := bookmarks.(type) {
+	case []gotenberg.Bookmark:
+		if len(b) == 0 {
+			return nil
+		}
+
+		for _, inputPath := range inputPaths {
+			err := engine.WriteBookmarks(ctx, ctx.Log(), inputPath, b)
+			if err != nil {
+				return fmt.Errorf("write bookmarks into '%s': %w", inputPath, err)
+			}
+		}
+	case map[string][]gotenberg.Bookmark:
+		for _, inputPath := range inputPaths {
+			filename := filepath.Base(inputPath)
+			if specificBookmarks, ok := b[filename]; ok {
+				err := engine.WriteBookmarks(ctx, ctx.Log(), inputPath, specificBookmarks)
+				if err != nil {
+					return fmt.Errorf("write bookmarks into '%s': %w", inputPath, err)
+				}
+			}
+		}
+	default:
+		return fmt.Errorf("bookmarks type '%T' not supported", bookmarks)
+	}
+
+	return nil
+}
+
 // FormDataPdfEmbeds extracts embedded file paths from form data.
 // Only files uploaded with the "embeds" field name are included.
 func FormDataPdfEmbeds(form *api.FormData) []string {
@@ -313,6 +387,7 @@ func mergeRoute(engine gotenberg.PdfEngine) api.Route {
 			form := ctx.FormData()
 			pdfFormats := FormDataPdfFormats(form)
 			metadata := FormDataPdfMetadata(form, false)
+			bookmarks := FormDataPdfBookmarks(form, false)
 			userPassword, ownerPassword := FormDataPdfEncrypt(form)
 			embedPaths := FormDataPdfEmbeds(form)
 
@@ -326,6 +401,13 @@ func mergeRoute(engine gotenberg.PdfEngine) api.Route {
 				return fmt.Errorf("validate form data: %w", err)
 			}
 
+			if b, ok := bookmarks.(map[string][]gotenberg.Bookmark); ok {
+				err = WriteBookmarksStub(ctx, engine, b, inputPaths)
+				if err != nil {
+					return fmt.Errorf("write bookmarks: %w", err)
+				}
+			}
+
 			outputPath := ctx.GeneratePath(".pdf")
 			err = engine.Merge(ctx, ctx.Log(), inputPaths, outputPath)
 			if err != nil {
@@ -342,6 +424,13 @@ func mergeRoute(engine gotenberg.PdfEngine) api.Route {
 				return fmt.Errorf("embed files into PDFs: %w", err)
 			}
 
+			if b, ok := bookmarks.([]gotenberg.Bookmark); ok {
+				err = WriteBookmarksStub(ctx, engine, b, outputPaths)
+				if err != nil {
+					return fmt.Errorf("write bookmarks: %w", err)
+				}
+			}
+
 			err = WriteMetadataStub(ctx, engine, metadata, outputPaths)
 			if err != nil {
 				return fmt.Errorf("write metadata: %w", err)
@@ -619,6 +708,41 @@ func writeMetadataRoute(engine gotenberg.PdfEngine) api.Route {
 	}
 }
 
+// writeBookmarksRoute returns an [api.Route] which can write bookmarks into PDFs.
+func writeBookmarksRoute(engine gotenberg.PdfEngine) api.Route {
+	return api.Route{
+		Method:      http.MethodPost,
+		Path:        "/forms/pdfengines/bookmarks/write",
+		IsMultipart: true,
+		Handler: func(c echo.Context) error {
+			ctx := c.Get("context").(*api.Context)
+
+			form := ctx.FormData()
+			bookmarks := FormDataPdfBookmarks(form, true)
+
+			var inputPaths []string
+			err := form.
+				MandatoryPaths([]string{".pdf"}, &inputPaths).
+				Validate()
+			if err != nil {
+				return fmt.Errorf("validate form data: %w", err)
+			}
+
+			err = WriteBookmarksStub(ctx, engine, bookmarks, inputPaths)
+			if err != nil {
+				return fmt.Errorf("write bookmarks: %w", err)
+			}
+
+			err = ctx.AddOutputPaths(inputPaths...)
+			if err != nil {
+				return fmt.Errorf("add output paths: %w", err)
+			}
+
+			return nil
+		},
+	}
+}
+
 // encryptRoute returns an [api.Route] which can add password protection to PDFs.
 func encryptRoute(engine gotenberg.PdfEngine) api.Route {
 	return api.Route{
@@ -658,6 +782,7 @@ func encryptRoute(engine gotenberg.PdfEngine) api.Route {
 }
 
 // embedRoute returns an [api.Route] which can add embedded files to PDFs.
+// TODO: attachments instead?
 func embedRoute(engine gotenberg.PdfEngine) api.Route {
 	return api.Route{
 		Method:      http.MethodPost,
@@ -676,7 +801,6 @@ func embedRoute(engine gotenberg.PdfEngine) api.Route {
 			if err != nil {
 				return fmt.Errorf("validate form data: %w", err)
 			}
-
 			err = EmbedFilesStub(ctx, engine, embedPaths, inputPaths)
 			if err != nil {
 				return fmt.Errorf("embed files into PDFs: %w", err)

pkg/modules/pdftk/pdftk.go

@@ -145,6 +145,11 @@ func (engine *PdfTk) WriteMetadata(ctx context.Context, logger *zap.Logger, meta
 	return fmt.Errorf("write PDF metadata with PDFtk: %w", gotenberg.ErrPdfEngineMethodNotSupported)
 }
 
+// WriteBookmarks is not available in this implementation.
+func (engine *PdfTk) WriteBookmarks(ctx context.Context, logger *zap.Logger, inputPath string, bookmarks []gotenberg.Bookmark) error {
+	return fmt.Errorf("write PDF bookmarks with PDFtk: %w", gotenberg.ErrPdfEngineMethodNotSupported)
+}
+
 // Encrypt adds password protection to a PDF file using PDFtk.
 func (engine *PdfTk) Encrypt(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error {
 	if userPassword == "" {

pkg/modules/qpdf/qpdf.go

@@ -172,6 +172,11 @@ func (engine *QPdf) WriteMetadata(ctx context.Context, logger *zap.Logger, metad
 	return fmt.Errorf("write PDF metadata with QPDF: %w", gotenberg.ErrPdfEngineMethodNotSupported)
 }
 
+// WriteBookmarks is not available in this implementation.
+func (engine *QPdf) WriteBookmarks(ctx context.Context, logger *zap.Logger, inputPath string, bookmarks []gotenberg.Bookmark) error {
+	return fmt.Errorf("write PDF bookmarks with QPDF: %w", gotenberg.ErrPdfEngineMethodNotSupported)
+}
+
 // Encrypt adds password protection to a PDF file using QPDF.
 func (engine *QPdf) Encrypt(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error {
 	if userPassword == "" {